Pinwiki says there isn't a setting for it.
https://www.pinwiki.com/wiki/index.php?title=Gottlieb_System_80#Free_Play_for_System_80_Games
I'm not familiar with System 80A games at all, but was able to get a Williams System 3 game essentially on free play by setting the replay to 10,000 points. If you're able to lower the replay level low enough it's basically the same thing.